Fair Value of Assets and Liabilities (Financial Instruments where Carrying Amounts and Fair Values May Differ) (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Assets:
Policy loans	$ 1,613,609	$ 1,541,480
Cash and cash equivalents	2,340,343	3,325,698
Accrued investment income	577,220	466,394
Reinsurance recoverables and deposit receivables	50,219,999	48,247,817
Receivables from parent and affiliates	687,750	678,028
Liabilities
Cash collateral for loaned securities	218,787	121,372
Fair Value
Assets:
Commercial mortgage and other loans	8,603,932	7,534,909
Policy loans	1,613,609	1,541,480
Short-term investments	31,101	21,101
Cash and cash equivalents	253,472	474,415
Accrued investment income	577,220	466,394
Reinsurance recoverables and deposit receivables	3,251,991	2,355,489
Receivables from parent and affiliates	95,755	157,566
Other assets	193,207	203,493
Total assets	14,620,287	12,754,847
Liabilities
Policyholders’ account balances - investment contracts	12,809,578	10,811,361
Cash collateral for loaned securities	218,787	121,372
Short-term debt to affiliates	5,004
Reinsurance and funds withheld payable	2,626,639	2,602,140
Payables to parent and affiliates	45,664	38,571
Other liabilities	730,432	880,884
Total liabilities	16,436,104	14,454,328
Carrying Amount
Assets:
Commercial mortgage and other loans	8,671,415	7,759,323
Policy loans	1,613,609	1,541,480
Short-term investments	31,101	21,101
Cash and cash equivalents	253,472	474,415
Accrued investment income	577,220	466,394
Reinsurance recoverables and deposit receivables	3,253,522	2,357,292
Receivables from parent and affiliates	95,755	157,566
Other assets	193,207	203,493
Total assets	14,689,301	12,981,064
Liabilities
Policyholders’ account balances - investment contracts	12,822,889	10,826,931
Cash collateral for loaned securities	218,787	121,372
Short-term debt to affiliates	5,004
Reinsurance and funds withheld payable	2,626,639	2,602,140
Payables to parent and affiliates	45,664	38,571
Other liabilities	730,432	880,884
Total liabilities	16,449,415	14,469,898
Level 1 | Fair Value
Assets:
Commercial mortgage and other loans	0	0
Policy loans	0	0
Short-term investments	31,101	21,101
Cash and cash equivalents	253,472	474,415
Accrued investment income	0	0
Reinsurance recoverables and deposit receivables	0	0
Receivables from parent and affiliates	0	0
Other assets	0	0
Total assets	284,573	495,516
Liabilities
Policyholders’ account balances - investment contracts	0	0
Cash collateral for loaned securities	0	0
Short-term debt to affiliates	0
Reinsurance and funds withheld payable	0	0
Payables to parent and affiliates	0	0
Other liabilities	0	0
Total liabilities	0	0
Level 2 | Fair Value
Assets:
Commercial mortgage and other loans	0	0
Policy loans	0	0
Short-term investments	0	0
Cash and cash equivalents	0	0
Accrued investment income	577,220	466,394
Reinsurance recoverables and deposit receivables	0	0
Receivables from parent and affiliates	95,755	157,566
Other assets	193,207	203,493
Total assets	866,182	827,453
Liabilities
Policyholders’ account balances - investment contracts	782,368	815,520
Cash collateral for loaned securities	218,787	121,372
Short-term debt to affiliates	5,004
Reinsurance and funds withheld payable	2,626,639	2,602,140
Payables to parent and affiliates	45,664	38,571
Other liabilities	699,638	849,278
Total liabilities	4,378,100	4,426,881
Level 3 | Fair Value
Assets:
Commercial mortgage and other loans	8,603,932	7,534,909
Policy loans	1,613,609	1,541,480
Short-term investments	0	0
Cash and cash equivalents	0	0
Accrued investment income	0	0
Reinsurance recoverables and deposit receivables	3,251,991	2,355,489
Receivables from parent and affiliates	0	0
Other assets	0	0
Total assets	13,469,532	11,431,878
Liabilities
Policyholders’ account balances - investment contracts	12,027,210	9,995,841
Cash collateral for loaned securities	0	0
Short-term debt to affiliates	0
Reinsurance and funds withheld payable	0	0
Payables to parent and affiliates	0	0
Other liabilities	30,794	31,606
Total liabilities	$ 12,058,004	$ 10,027,447